Process for the production of saturated carbonyl compounds from unsaturated hydrocarbons



United States Patent 3,400,160 PROCESS FOR THE PRODUCTION OF SATU- RATED CARBONYL COMPOUNDS FROM UNSATURATED HYDROCARBONS Sumi Masaki, Fujisawa-shi, Tadashi Ohmori, Kawasakishi, Takeshi Hoshino, Meguro-ku, Tokyo, and Yasuo Fujiwara, Suginami-ku, Tokyo, Japan, assignors to Nippon Oil Company, Limited, Tokyo, Japan, a corporation of Japan No Drawing. Filed May 11, 1964, Ser. No. 366,593 Claims priority, application Japan, May 25, 1963, 38/27,153 4 Claims. (Cl. 260-597) The present invention relates to a process for the production of saturated carbonyl compounds from unsaturated hydrocarbons, and more particularly to a process for the production of saturated carbonyl compounds by reacting an unsaturated hydrocarbon with a solution of mercu-ric nitrate in nitric acid and nitrous acid or a compound of nitrous acid.

Heretofore, various processes have been proposed for the oxidation of unsaturated hydrocarbon using a mercuric salt. As mercuric salt for such purpose mercuric sulfate, nitrate, perchlorate, sulfonate and like have been found effective. However, oxidation products obtained by these processes are mainly unsaturated compounds. For example, main product from propylene is acrolein and main product from butene-l is methyl vinyl ketone. Thus, saturated carbonyl compounds could not be obtained by these processes in substantial amount.

It has also been known that when mercuric nitrate is used as the mercuric salt in such process and the solution or suspension of the mercuric salt in nitric acid used as the oxidizing solution further contains certain other nitrates, such as ferric, silver, thallium or chromium nitrate, mainly saturated carbonyl compounds are produced from unsaturated hydrocarbons, for example, acetone from propylene and methyl ethyl ketone from butene-l.

We Have noW discovered that in the oxidation of unsaturated hydrocarbon with a solution of mercuric nitrate in nitric acid, unsaturated hydrocarbon can be converted mainly to saturated carbonyl compounds when a small amount of nitrous acid or a compound of nitrous acid is used in the oxidizing solution. Based on this discovery, the present invention comprises a process for the production of saturated carbonyl compounds by oxidizing an unsaturated hydrocarbon using as the oxidizing agent a solution of mercuric nitrate in nitric acid characterized in that the solution of mercuric nitrate in nitric acid contains nitrous acid or a compound of nitrous acid.

By using a small amount of nitrous acid or a compound of nitrous acid in the solution of mercuric nitrate in nitric acid according to the present invention saturated carbonyl compounds are produced from unsaturated hydrocar-bon without appreciable production of unsaturated carbonyl compounds. Thus, according to the process of the present invention acetone can be produced from propylene, methyl ethyl ketone from butene-l, and methyl ethyl ketone and diethyl ketone from butene-2.

Compounds of nitrous acid used in the process of the present invention may either be an inorganic nitrous acid compound, for example, metal nitrite, such as sodium, potassium, mercury, lead nitrite, or an organic nitrous acid ester, such as isoamyl nitrite. Alternatively, a compound which reacts with water or nitric acid of the oxidizing solution and produces nitrous acid in situ may be used. For example, the process of the present invention can also be carried out using a solution of mercuric nitrate in nitric acid and producing in the solution nitrous acid by blowing nitric oxide or nitrogen dioxide into the solution or by adding to the solution a compound con- 3,400,160 Patented Sept. 3, 1968 taining a metal in a lower oxidation stage, e.g., a ferrous salt.

In the oxidation reaction of unsaturated hydrocarbon by mercuric nitrate, first a mercuric nitrate-unsaturated hydrocarbon complex compound is formed as intermediate. The intermediate complex compound then decomposes and carbonyl compounds are produced. When the unsaturated hydrocarbon is a lower hydrocarbon, such as ethylene, propylene or butylene, the mercuric nitrate-unsaturated hydrocarbon complex compound formed is -very stable at temperatures below 60 C. and there is a relatively long induction period before decomposition sets in.

Upon decomposition of the mercuric nitrate-unsaturated hydrocarbon complex compound which has been formed by the primary reaction of the unsaturated hydrocarbon and mercuric nitrate mainly saturated carbonyl compounds are produced when a small amount of nitrous acid or a compound of nitrous acid is present in the solution of mercuric nitrate in nitric acid according to present invention whereas the products are mainly unsaturated carbonyl compounds when nitrous acid or a compound of nitrous acid is not present. Also, it has been found that when nitrous acid or a compound of nitrous acid is used in the solution of mercuric nitrate in nitric acid according to present invention, the induction period preceding the decomposition of mercuric nitrate-unsaturated hydrocarbon complex compound can be reduced to almost zero so that complex formation reaction and complex decomposition reaction can be effected almost simultaneously. Hence, the process of the present invention can be carried out in one-step continuous operation. The process of the present invention may also be carried out in two-step operation wherein in the first step a mercuric nitrateunsaturated hydrocarbon complex compound is formed by passing an unsaturated hydrocarbon into a solution of mercuric nitrate in nitric acid and in the second step the complex compound formed is decomposed to produce saturated carbonyl compounds without significant induction period by adding nitrous acid or a compound of nitrous acid to the nitric acid solution containing the complex compound.

In the process of the present invention either a single unsaturated hydrocarbon or a mixture of unsaturated hydrocarbons may be used. The unsaturated hydrocarbon may also be used in admixture with other substances which do not enter the reaction of the present invention, such as oxygen, hydrogen, carbon monoxide, carbon dioxide, saturated hydrocarbon and the like. Such substances do not enter the reaction and do not have unfavorable influence on the reaction of the present invention. In the process of the present invention these substances act merely as diluents and the unsaturated hydrocarbon is selectively oxidized.

In the process of the present invention, the reaction temperature may be varied over a wide range depending on the kind of unsaturated hydrocarbon to be oxidized, composition of the oxidizing solution and the kind of nitrous acid compound used. But, generally, use ful range of the reaction temperature is from 0 C. to C, Generally, the process of the present invention is carried out under ordinary pressure, but higher pressure may also be used.

As described above, when an unsaturated hydrocarbon is introduced into a solution of mercuric nitrate in nitric acid the unsaturated hydrocarbon forms with the mercuric nitrate mercuric nitrate-unsaturated hydrocarbon complex compound and the complex compound so formed decomposes in the presence of nitrous acid or a compound of nitrous acid to produce saturated carbonyl compounds. For example, when propylene is used as the unsaturated hydrocarbon, mercuric nitrate-propylene complex compound containing mercuric nitrate and propylene in equimolecular proportion is formed under ordinary pressure and temperature. In the presence of nitrous acid or a compound of nitrous acid the complex compound decomposes immediately and acetone is produced as the sole product. Mercuric nitrate is reduced by this reaction. Oxidizing solution which has been reduced and become inactive may be removed from the reactor by suitable method, reactivated with air or oxygen or with fresh nitric acid and may be reused. Thus, the oxidizing solution can be recycled as catalyst for the oxidation of unsaturated hydrocarbon in the process of the present invention.

Saturated carbonyl compounds produced in the oxidizing solution can be separated and recovered using conventional methods, such as distillation, solvent extraction, etc. If the reaction temperature, i.e., the temperature of the oxidizing solution is maintained higher than the boiling temperature of the unsaturated hydrocarbon and the unsaturated hydrocarbon or a mixture of the unsaturated hydrocarbon and an inert gas such as hydrogen or steam is passed through the solution, the saturated carbonyl compounds formed will pass out continuously from the top of the reactor with the unreacted unsaturated hydrocarbon in vapor state and can be recovered from the reactor overhead effiuent stream using conventional condensation method.

Examples illustrating the process of the present invention will be set forth below. It will be understood that the present invention is not limited to those described in the examples.

Example I In a glass reactor equipped with an agitator, gas inlet, and gas outlet 200 ml. of an oxidizing solution which has been prepared by dissolving 66.7 g. of mercuric nitrate, 18 ml. of nitric acid of specific gravity 1.38 and a nitrous compound of an amount as shown in the following table in water were placed and heated, When the temperature of the solution reached predetermined reaction temperature propylene gas (purity 90%, the balance being propane) was introduced into the oxidizing solution at a rate of 150 ml./min. while agitating the solution. The reaction was continued for 3 hours. Carbonyl compounds entrained in the efiiuent gas were caught in a 200 ml. water trap maintained at 5 C. and analysis was made by gas chromatography.

The results are shown in the following table.

Composition of carbonyl compds.

Nitrite of N01 temp.,

Hg C. Acetone Acroleln Proplonaldehyde NaNO-r 0.001 75 100. Trace Trace NaNO2-- 0. 0005 75 66. 6 30. 2 3. 2 NaNO: 0.01 65 100.0 0 0 NaNOz- 0.005 65 70.3 25.8 4.0 KNO: 0.005 75 100. 0 Trace Trace KNO2 0. 001 75 53.9 39. 3 6. 8 KNOg 0 01 65 100. 0 Trace Trace KNO2 005 65 73. 3 23. 0 3. 7 Hg(NO 0 0025 75 100. 0 0 0 Hg(NO2)2 0 001 75 67. 9 31.7 0.3 Hg(NO2)2 0. 0025 65 100. 0 0 Trace Hg(NO2)2 0. 0005 65 66. 9 28. 3 4. 8

Example II Reaction of propylene was conducted at 75 C. for 3 hours using the same appartus and same procedure as described in Example 1, except that the oxidizing solution was prepared in a preliminary step by blowing nitrogen dioxide gas into mercuric nitrate-nitric acid solution at a rate of 50 mL/min. for minutes instead of using mercuric nitrate-nitric acid solution containing a nitrite. Carbonyl compound produced by the oxidation was acetone except traces of acrolein and propionaldehyde. Acetone was produced at an average rate of 96.8 millimols per liter of the oxidizing solution per hour.

"4 Example III Same procedure as described in Example II was repeated except that the oxidizing solution was prepared by blowing nitric oxide gas into the mercuric nitrate-nitric acid solution for 5 minutes instead of nitrogen dioxide gas. Yield of acetone based on consumed propylene was 'Acetone production rate was 75.6 millimols per 1 liter of the oxidizing solution per hour.

Example IV Nitric oxide gas and propylene gas were simultaneously and continuously blown into the oxidizing solution at a rate of 50 ml./min., respectively, using the same apparatus and the same oxidizing solution as described in Example I. The reaction was conducted at 75 C. for 3 hours. Acetone was the sole oxidation product and produced at an average rate of 47.9 millimols/l./hr.

Example V In a 300 ml. glass reactor equipped with an agitator, thermometer, gas inlet and gas outlet 200 ml. of an oxidizing solution containing mercuric nitrate in a concentration of 1 mol/l. and nitric acid in a concentration of 1 mol/l. were placed. Propylene gas was passed into the oxidizing solution at room temperature to form complex compound. To the resultant solution sodium nitrite was added in such amount as to make the concentration of sodium nitrite in the solution 50 millimols/l. under agitation and the reactor was placed in a water bath at 45 C. Decomposition of the complex compound started immediately and 54.2% of the complex compound was decomposed in minutes. Yield of acetone based on propylene consumed was 100%.

When the amount of sodium nitrite was increased to 100 millimols/l. and 200 millimols/ 1., 75.3% and 100.0% of the complex compound was decomposed in 160 minutes with production of acetone. Whereas when no sodium nitrite was added the complex compound was completely stable and no change was observed after 160 minutes in its concentration.

Example VI Various nitrites were tested using the same apparatus and the same reaction conditions as are described in Example V with the following results.

of 25 mm. and a height of 500 mm. was filled with 230 ml. of an oxidizing solution containing 1 mol/l. of mercuric nitrate and 2 mols/l. of nitric acid. Propylene gas (purity 90%, the balance being propane) was introduced from a lower part of the reactor at 20 C., in small bubbles and at a rate of 230 ml./min. under agitation. After 25 minutes the absorption of propylene became inappreciable, indicating the completion of the complex-forming reaction. 200 ml. of the oxidizing solution containing the complex compound thus formed was then placed in a 300 ml. glass reactor equipped with an agitator, thermometer and gas outlet and 4 ml. of aqueous 4 N sodium nitrite solution were added. The reactor was then placed on a water bath maintained at 45 C. to decompose the complex compound. The decomposition reaction was continued for 50 minutes. At the end of 50 minutes it was found that 89.3% of the complex compound has been decomposed. Yields of products based on consumed propylene were found as follows: .Acetone 58.7%, acetic acid 3.1%, carbon dioxide 0.2%. 25.1% of propylene was regenerated from the complex compound in the decomposition.

Acetone was recovered from the oxidizing solution containing the decomposition products using a glass stripping tower having an internal diameter of 27 mm., a height of 520 mm. and filled with Raschig rings at 60 C. and under 150 mm. Hg, using steam. 97.8% of acetone in the solution distilled out overhead.

Example VIII Complex compound formation reaction was conducted in an oxidizing solution containing 1 mol/l. of mercuric nitrate, 2 mols/l. of nitric acid and 100 millimols/l. of sodium nitrite, using the same apparatus and conditions as described in Example VII. In the case of this example, complex compound formed was partially decomposed by the presence of the sodium nitrite and acetone was produced in the oxidizing solution in a concentration of 123 millimols/l. during the complex formation stage of 60 minutes. The oxidizing solution was then subjected to decomposition without further addition of nitrite at 45 C. for 60 minutes. 73.1% of the complex compound was decomposed in total. Yields of products based on propylene consumed were as follows. Acetone 39.8%, acetic acid 4.0%, carbon dioxide 0.3%. 25.8% of propylene was regenerated from the complex compound in the decomposition.

Example IX Complex compound was prepared and decomposed in the same manner as described in Example VII. Reduced oxidizing solution remaining after acetone has been separated was reactivated by heating at 90 C. for 1 hour, and the reactivated oxidizing solution was used again for the oxidation of propylene under the same conditions as described in Example VII. In the complex formation step of 60 minutes acetone was produced in a concentration of 99 millimols/l. Decomposition reaction was conducted at 45 C. for 60 minutes and the yields of products based on consumed propylene were as follows: Acetone 57.1%, acetic acid 5.5%. 0.3% of propylene was regenerated from the complex compound in the decomposition.

Example X 200 ml. of an oxidizing solution containing 1 mol/l. of mercuric nitrate and 1 mol/l. of nitric acid were placed in a tubular glass reactor having an internal diameter of 25 mm. and heated to 75 C. Ethylene gas having a purity of 99.7% was blown into the solution from the bottom of the reactor in finely divided bubbles. Immediately after the introduction of ethylene gas commenced, an aqueous solution of sodium nitrite was added to the oxidizing solution in an amount to make the concentration of sodium nitrite in the solution to 100 millimols/l. Acetaldehyde which passed out from the reactor entrained in the unreacted ethylene gas during the reaction period of 3 hours totalled 21 millimols per liter of the oxidizing solution.

Example XI Into 200 ml. of an oxidizing solution containing 1 mol/l. of mercuric nitrate and 2 mols/l. of nitric acid, ethylene gas having a purity of 99.7% was blown at 20 C. to form complex compound. The resulting oxidizing solution containing the complex compound was placed in a glass reactor equipped with an agitator, thermometer and gas outlet. Sodium nitrite was added in an amount to make the concentration of sodium nitrite in the solution to 200 millimols per liter and the temperature of the solution was raised to 45 C. After reaction of 1.5 hours, 53.0% of the complex compound was decomposed and acetaldehyde was produced. When sodium nitrite was not added the complex compound was completely stable at 45 C.

Example XII 190 ml. of an oxidizing solution containing 0.5 mol/l. of mercuric nitrate, 1 mol/l. of nitric acid and 0.1 mol/l. of sodium nitrite were placed in a tubular glass reactor having an internal diameter of 25 mm. and heated to C. Butene-l having a purity of 98.9% was introduced into the oxidizing solution and the reaction was continued for 3 hours. 78.7 millimols of carbonyl compounds were obtained per liter of the oxidizing solution. Yields of individual carbonyl compounds based on butene-l consumed were as follows: Acetaldehyde 1.8%, acetone 4.6%, methyl ethyl ketone 62.1%, methyl vinyl ketone 10.4%, diethyl ketone 10.6%, methyl isobutyl ketone 10.5%.

Example XIII 230 ml. of an oxidizing solution containing 1 mol/l. of mercuric nitrate and 2 mol/l. of nitric acid were placed in a glass reactor equipped with an agitator, thermometer, gas inlet and gas outlet. Butene-Z gas was blown into the oxidizing solution at a rate of 300 ml./min. at 20 C. to form complex compound. Then, the temperature of the solution was raised to 45 C. and at the same time sodium nitrite was added to make the concentration of sodium nitrite in the solution to millimols/l. to decompose the complex compound. Production rate of total carbonyl compounds and the yields of individual carbonyl compounds based on butene-2 consumed are shown in the following table.

Whereas, when no sodium nitrite was added the complex compound remained complete stable.

We claim:

1. A process which comprises reacting at least one aliphatic ethylenically unsaturated hydrocarbon with an oxidizing agent consisting of a nitric acid solution of mercuric nitrate to form a mercuric nitrate-hydrocarbon complex, decomposing said complex in the presence of nitrous acid at a temperature in the range of from about 0 C. to about 100 C., said nitrous acid being present in an amount sufficient to form the corresponding member of the group consisting of saturated aldehydes and saturated ketones, and recovering the thus formed saturated compounds.

2. A process as claimed in claim 1 wherein the hydrocarbon is ethylene.

3. A process as claimed in claim 1 wherein the hydrocarbon is propylene.

4. A process as claimed in claim 1 wherein the hydrocarbon is butylene.

References Cited UNITED STATES PATENTS 3,172,914 3/1965 Fujiwara et al. 260597 DANIEL D. HORWITZ, Primary Examiner. 

1. A PROCESS WHICH COMPRISES REACTING AT LEAST ONE ALIPHATIC ETHYLENICALLY UNSATURATED HYDROCARBONS WITH AN OXIDIZING AGENT CONSISTING OF A NITRIC ACID SOLUTION OF MERCURIC NITRATE TO FORM A MERCURIC NITRATE-HYDROCARBON COMPLEX, DECOMPOSING SAID COMPLEX IN THE PRESENCE OF NITROUS ACID AT A TEMPERATURE IN THE RANGE OF FROM ABOUT 0*C. TO ABOUT 100*C., SAID NITROUS ACID BEING PRESENT IN AN AMOUNT SUFFICIENT TO FORM THE CORRESPONDING MEMBER OF THE GROUP CONSISTING OF SATURATED ALDEHYDES AND SATURATED KETONES, AND RECOVERING THE THUS FORMED SATURATED COMPOUNDS. 